Pyridazone derivatives

ABSTRACT

New and valuable pyridazone derivatives, especially mtrifluoromethylphenyl pyridazone derivatives, and a process for controlling unwanted plants with these compounds.

Umted States Patent [151 3,697,522 Reicheneder et a]. [451 Oct. 10, 1972[541 PYRIDAZONE DERIVATIVES [72] Inventors: Franz Reicheneder; RudolfKropp, [56] References Cited both of Ludwigshafen; Adolf TED Fischer,Mutterstadt, all of Germany UNI STATES PATENTS & @2222: 13112223222;211:2222: 22422 tiengesellschaft, Ludwigshafen/ .BDQ ELQFEE JLPrimary Examiner-Nicholas s. Rizzo [22] Filed: Feb. 3, 1969Attorney-Johnston, Root, OKeeffe, Keil, Thompson 21 Appl. No.: 796,182 &shm'flefi 30 i F A ll Pn Ba [57] ABS CT orei ti t ta gn pp ca on on yNew and valuable pyridazone derivatives, especially Feb- 10, Pderivatives and a process for controlling unwanted plants with these[52] US. Cl. ..260/250 A, 71/92 compounds [51] Int. Cl. ..C07d 51/04[58] Field of Search ..260/25O 4 Claims, N0 Drawings PYRIDAZONEDERIVATIVES The present invention relates to new pyridazonederivatives,viz. substituted l-m-trifluoromethylphenyl pyridazonederivatives.

It is known to use chloropyridazone-(6) as (British Pat. No. 917,849).

It is further known to use N-p-chlorophenyl-N- dimethylurea as aherbicidal ingredient. The use of 2-chloro-4,6-bis-(ethylamino)-s-triazine as a herbicidal ingredient isalso known. However, the results obtainable with these compounds areoften unsatisfactory.

An object of the invention is new and valuable pyridazone derivatives. Afurther object of the invention is new and valuablem-trifluoromethylphenyl pyridazone derivatives. Another object of theinvention is a process for controlling unwanted plants with new andvaluable pyridazone derivatives without damaging crop plants. These andother objects of the invention are achieved by pyridazone derivativeshaving the formula l-phenyl-4-methoxy-5 a herbicidal ingredient in whichX denotes an alkoxy, thioalkyl, amino, acctylamino, halo-acetylamino,dimethylformamidine, mcthyllormamidinc, alkylamino or an isocyanatoradical, the group NH-CO-COOR, NHCO-COSR, NHCONHR, -NHCOOR, NHCOSR,

R denoting a substituted or unsubstituted alkyl, cycloalkyl, aralkyl oraryl radical or hydrogen, and the salts of these compounds, and in whichY denotes chlorine, bromine or an alkoxy or thioalkyl group.

By salts we mean the alkali and ammonium salts of derivatives.Production of l-m-trifluoromethylphenyl-4-methoxy-5 -chloropyridazone 8parts by weight of a 30 percent by weight methanolic sodium methylatesolution is added to 9 parts ofl-mtrifluoromethylphenyl-4,5-di-chloropyridazone-(6) in l00 parts ofmethanol and this mixture boiled for 30l-m-trifluoromethylphenyl-4-methoxy-S- chloropyridazone-( 6) lm-trifluoromethylphenyl-4-methoxy-5- bromopyridazone-(6)l-m-trifluoromethylphenyl-4-amino-5- bromopyridazone-( 6)l-m-trifluoromethylphenyl-4-amino-5- chloropyridazone-( 6) mp. 152 to153C m.p. 154C m.p. 172 to 174C m.p. 174 to 175C Production ofl-(m-trifluoromethyl)-phenyl-4,5- dichloropyridazone-(6) A solution of212.5 parts by weight of mtrifluoromethylphenyl hydrazonium chloride in2,000 parts of a 10 percent by weight aqueous hydrochloric acid isheated to to C.; 169 parts of mucochloric acid is thenadded. The mixtureis stirred for two hours at 80 to 90 C., during which time thepyridazone, is deposited at the bottom of the flask in the form of anoil. Upon cooling the pyridazone solidities to give a solid crystallinemass. Yield: 300 parts 97 percent of the theory; melting point: 90 to 91.5 C. (from methanol).

The new compounds may be applied as herbicides in the form of solutions,emulsions, suspensions or dusts. The form of application dependsentirely on the purpose for which the agents are being used; in any caseit should ensure a fine distribution of the active ingredient.

For the preparation of solutions to be sprayed direct water mineral oilfractions with medium to high boiling points, such as kerosene or dieseloil, coal-tar oils and oils of vegetable and animal origin, cyclichydrocarbons, such as tetrahydronaphthalene, and alkylated naphthalenesare suitable.

Aqueous formulations may be prepared from emulsion concentrates, pastesor wettable powders by adding water. To prepare emulsions theingredients as such or dissolved in a solvent may be homogenized inwater by means of wetting or dispersing agents, e.g., polyethyleneoxide. adducts. Concentrates which are suitable for dilution with watermay be prepared from active ingredient, emulsifying or dispersing agentand possibly solvent.

Dusts may be prepared by mixing or grinding the active ingredients witha solid carrier, e.g., clay, diatomite or fertilizer.

The following Examples illustrate the use of the compounds according tothe invention.

EXAMPLE 1 Pots having a diameter of 8 cm are filled with loamy sandysoil in a greenhouse and then sown with the seeds of Indian corn (Zeamays), cotton (Gossypium sp.), annual meadow grass (Poa annua), slenderfoxtail (Alopecurus myosuroides), barnyard grass (Echinoch 10acrus-galli), large crabgrass (Digitaria sanguinalis), white goosefoot(Chenopodium album), chickweed (Stellaria media) and amaranth pigweed(Amaranthus retroflexus). The soil prepared in this manner issubsequently treated with 3 kg per hectare ofl-mtrifluoromethylphenyl-4-methoxy-5-chloropyridazone- (6) (I), and forcomparison, with 3 kg per hectare of 1-phenyl-4-methoxy-S-chloropyridazone-(6) (II) and 3 kg per hectare ofN-p-chlorophenyl-N-dimethylurea (III), these amounts of the activeingredients each being dispersed in 500 liters of water per hectare.

After four to five weeks it is ascertained that I has a strongerherbicidal action than II and superior plant compatibility over III.

The results of the experiment may be seen from the following table:

Active ingredient In a greenhouse the plants cotton (Gossypium sp.),rice (Oryza sativa), annual meadow grass (Poa annua), slender foxtail(Alopecurus myosuroides), barnyard grass (Echinochloa crus-galli), largecrabgrass (Digitaria sanguinalis), white goosefoot (Chenopodium album),henbit (Lamium amplexicaule) and amarauth pigweed (Amaranthusretroflexus) are treated at a growth height of from 3 to 12 cm with 2kgper hectare of l-m-trifluoromethylphenyl-methoxy-S- chloropyridazone-(6)(I), and, for comparison, with 2 kg per hectare of l-phenyl-4-methoxy-5-chloropyridazone-(6)(Il) and 2 kg per hectare ofN-pchlorophenyl-N-dimethylurea (III), these amounts of the activeingredients each being dispersed in 500 liters of water per hectare.

After three to four weeks it is ascertained that I has a strongerherbicidal action than II and superior plant compatibility over III.

The results of the experiment may be seen from the following table:

Active ingredient O damage 100 total destruction EXAMPLE 3 A site issown with annual meadow grass (Poa annua), slender foxtail (Alopecurusmyosuroides), barnyard grass (Echinochloa crus-galli), large crabgrass(Digitaria sanguinalis), white goosefoot (Chenopodium album), chickweed(Stellaria media) and amaranth pigweed (Amaranthus retroflexus) andsprayed on the same day with 5 kg per hectare ofl-mtrifluoromethylphenyl-4-methoxy-5-chloropyridazone- (6) (I), and, forcomparison, with 5 kg per hectare of 2-chloro-4,6-bis-(ethylamino)-s-triazine (IV), these amounts of the activeingredients each being dispersed in 500 liters of water per hectare.

Whereas the plants treated with IV develop normally at first andgradually wither, the plants on the part of the site treated with Ideveloped marked chlorosis even during germination; after-4 to 5 weeksall plants treated with I are almost completely withered, whereas bothbroadleaved and grassy weeds are still growing on that part of the sitetreated with IV.

' EXAMPLE 4 A site with annual meadow grass (Poa annua), slender foxtail(Alopecurus myosuroides), barnyard grass (Echinochloa crus-galli), largecrabgrass (Digitaria sanguinalis), white goosefoot (Chenopodium album),henbit (Lamium amplexicaule) and amaranth pigweed (Amaranthusretroflexus) growing on it is treated, at a growth height of the weedsof 2 to 7 cm, with 5 kg per hectare of l-m-trifluoromethylphenyl-4-methoxy-5-chloropyridazone-(6) (I), and, for comparison with 5 kg perhectare of 2-chloro-4,6-bis- (ethylamino)-s-triazine (IV), these amountsof the active ingredients each being dispersed in 500 liters of waterper hectare. After a few days it is observed that the broadleaved andgrassy weeds treated with I develop chlorosis and wither, whereas theweeds treated with IV continue to grow normally..After four to eightweeks both broadleaved and grassy weeds treated with I are completelywithered, whereas some weeds continues to grow on the areas treated withIV.

The following active ingredients are biologically as effective as I inExamples 1,2,3 and 4:l-m-trifluorophenyl-4-methoxy-S-bromopyridazonel-m-trifluorophenyl-4-amino-5-bromopyridazone-(6)

2. 1-m-trifluoromethylphenyl-4-methoxy-5-bromopyridazone-(6). 3.1-m-trifluoromethylphenyl-4-amino-5-bromopyridazone-(6). 4.1-m-trifluoromethylphenyl-4-amino-5-chloropyridazone-(6).